Table 3.

Relative Merits of DIGE and ICAT Techniques for Protein Thiol Quantification

	advantages	disadvantages
DIGE	More confident protein identification, better sequence coverage More effective at identifying protein oxidative isoforms Easier implementation of statistics for multiplexed quantification Suitable for large scale screening	Not amenable for analyzing basic, hydrophobic, and large proteins Unable to locate the exact sites of cysteine oxidative modifications Comigration of proteins may interfere with accurate protein identification and thiol quantification May overlook low-abundant proteins
ICAT	Able to locate the exact sites of redox-sensitive cysteines Amenable to multidimensional separation and enhances the detection of low-abundant proteins Suitable for large scale screening	Less protein sequence coverage than 2DE Multiple ICAT experiments are required to establish statistical significance for quantification and may be time-consuming Overlapping ions in MS spectra may interfere with accurate quantification and identification